Update web-ui-use-cases.md

Author: ddematheu2

articles/communication-services/concepts/ui-library/includes/web-ui-use-cases.md

@@ -18,6 +18,7 @@ Get more conceptual documentation, quickstarts, and examples in the [UI Library
 | ------------------- | ------------------------------------------------------ |
 | Call types          | Join a Microsoft Teams meeting                                     |
 |                     | Join an Azure Communication Services call by using a group ID   |
+|                     | Join an Azure Communication Services [Room](../../rooms/room-concept.md) |
 | [Teams interoperability](../../teams-interop.md)      | Join the call lobby                                             |
 |                     | Display a transcription and recording alert banner               |
 | Call controls       | Mute and unmute a call                                       |